A moog sub phatty and theremin to run through.
Looking to be able to get over drums, bass and two guitars.
Will be playing both instruments but not simultaneously
Any recommendations?
Any input would greatly be appreciated
Thanks!!
The whole amp thing has been gone over numerous times in these forums. Traynor K4, Roland KC550, old Peavey KB300, (new Peavey amps are worthless), if you have unlimited funds, Motion Sound amps are awesome! Or you can get yourself a PA amp of a few hundred watts and a 15" two or three way speaker. 
Thanks!
I know its a tired out post but an important one.
These amps have two channels? One for theremin .one for moog?
Enough juice to get over everything?
The Roland has four inputs. Peavey’s generally have two. Any amp can be made to have more inputs. If an amp you like only has one input, get one of these: http://www.parts-express.com/pe/showdetl.cfm?partnumber=245-042 All the amps mentioned should get plenty loud enough. There’s always the PA option…if you want to blow everyone else off the stage. 
The Peavey KB series comes in various wattage and speaker combinations. I use two KB100s in stereo. The KB 100 is actually 75 Watts RMS with a 15" speaker and a high frequency driver, with three inputs, and can be found used for $150 or less. They are quite loud. I paid a tech to replace any parts of the amps which were out of spec, and match the output levels. You may not need stereo for the SPh and Theremin, each of which are mono. Another possibility for you is a Roland Jazz Chorus.
After doing the same investigative search, I ended up with a qsc k-12 1000 watt Powered PA speaker. I am quite happy.
Good Choice. Add a K-sub and boOM.
I got sucked into getting another k-12 to round out the possibilities of a stereo PA system, but the sub is on my lust and envy list, prob will be an x-mas gift to my self, or launder it under the family budget radar if a 2 year 0% financing presents sometime in the fall after having painted the house and other maintenance costs are allocated.
this is probably overkill for what you are doing but i run my little phatty through a 800 watt bass amp into 2 JBL 15s and 1 JBL 18. you can feel the low end through your stomach. i can only imagine the sub phatty to sound even more brutal.
i saw a guy run a theremin through a marshall 100 jmp non master volume once. it shredded my face off. he was using it in a devo cover band.
Total noob question, as I’m a synth noob, but I’ve got a Sub Phatty on the way. The only option I have right now in terms of amp is a Yamaha MSR 100 active PA speaker. Do I dare?
If i may help.
The Roland Kc550 sound great, has fantastic low end…but just isn’t loud enough. With drums, guitars, etc you have the push the amp to about 80% of it’s capacity. Its great for a band that does not incorporate drums into the mix.
Ive got some K10s on the way and hope these will work better.
Curious if the low end of the sub phatty will damage the K10’s (i don’t have a Ksub…yet)
Yes! Great place to start out.
There is a band in Chicago called Distant Cities.
They fucking rock.
They have a Voyager with a stack of Orange Amps.
It sounds so incredibly good.
So…
Orange.
There.
I know this is crazy, but,
I got a stupid deal on one of these.
420W and it handles the Sub Phatty fine.
I only want to use it for really small gigs and home practice.